The subject matter disclosed herein relates to belts utilized in elevator systems for suspension and/or driving of the elevator car and/or counterweight.
Conventional elevator systems use rope formed from steel wires as a lifting tension load bearing member. Other systems utilize a lifting belt formed from a number of steel cords, formed from steel wires, retained in an elastomeric jacket. The cords act as the load supporting tension member, while the elastomeric jacket holds the cords in a stable position relative to each other, and provides a frictional load path to provide traction for driving the belt.
More recent developments in the area of composites include the use synthetic fibers such as carbon fiber and glass fiber to provide a higher strength to weight ratio than steel. The fibers are first impregnated with thermoset resins and then cured to form rigid and brittle composite cords that are later surrounded with an elastomer to provide traction for the belt. Although a belt with carbon fiber and thermoset resin will provide improved strength to weight advantages compared to steel cord belt, significant manufacturing, performance and durability challenges exist. For example, the long curing cycle of the thermoset resin and entrapment of air voids during cure present a manufacturing challenge. Further, the rigid construction is contrary to the desire for a flexible belt capable of many thousands of bending cycles without brittle or fatigue failure in the field.